Known models of in-pavement, omni-directional taxiway lights rely principally on designs that protrude somewhat above the pavement. For example, ADB-Alnaco, Inc. of Columbus, Ohio (a subsidiary of Siemens) and Crouse-Hinds of Windsor, Conn. (a unit of Cooper Industries) market popular lamps consisting of a housing supporting a series of vertically oriented windows arranged in a "lighthouse" configuration. However, such protruding designs suffer from significant disadvantages. Even with tapered risers of the sort used by those companies' products, such housings have a tendency to rip out of the ground when contacted by scraping equipment such as snowplows. That results in expensive damage to equipment and can delay reopening of an airport after weather interruptions.
Known flush-mounted airport lights are expensive, difficult to manufacture, unable to support high loads (such as from a wheel of a jumbo jet), or do not meet the FAA specifications for low-angle light intensity. The inventive apparatus, by contrast, suffers from none of those problems, yet is implemented in a design that protrudes less that one half of a centimeter above the ground, as opposed to two or three centimeters, common to the other lights on the market.
It is therefore a principal object of the invention to provide a flush-mounted, in-pavement, omni-directional taxiway light.
It is another object of the invention to provide a-taxiway light that provides high light intensity at low angles while remaining substantially flush with the taxiway surface.
It is another object of the invention to provide a flush light that is easy to produce.
It is another object of the invention to provide a flush light and associated housing that can support high loads.
It is another object of the invention to provide a substantially convex-top flush light that allows rain to flow off to the sides of the light without pooling in depressions in the light.
It is another object of the invention to provide an optical system for a taxiway light that can redirect a substantial portion of the light to nearly right angles.
It is another object of the invention to provide a taxiway light system with a conjugate pair of lenses, the top one of which has a concave central inclusion at its bottom and a convex top surface, and the bottom one of which is configured to act as a condenser.
It is another object of the invention to provide a lens system that redirects a portion of a vertical light beam to bend that portion more that 90.degree., and then to reflect such portions to reinforce the light intensity at angles slightly less than 90.degree. bent from vertical.
It is another object of the invention to provide a flush light system with a top, beam-spreading lens, and a bottom lens that focuses the beam to a focal point at or below the bottom surface of the top lens, thereby allowing light to spread across substantially the entire surface of the top lens.